Hall-voltage device

ABSTRACT

A Hall-voltage device comprising means for generating a magnetic field and a fluid-containing body in this field, which fluid contains charged particles. The device further comprises means for moving the body relative to the magnetic field in a plane essentially normal to said field and means for collecting and measuring the Hall-voltage produced in the body upon such a movement, the latter means consisting of two electrodes connected to spaced apart points of the fluid.

FEFSEEUZ {3R 3418253I53 United States Patent 1191 v 1111 3,823,333 Spierings July 9, 1974 1 1 HALL-VOLTAGE DEVICE 3,532,233 1 5421518011.; l [76] Inventor: Ferdlhahd 5 Framscus 3,539,921 11/1970 c5112 310/11 Gerardus Splermgs, Asserpark 11, Wagenmgen, Netherlands Primary Examiner j D Miller [22] Filed: Aug. 9, 1972 Assistant ExaminerPatrick Salce Attorney, Agent, or FirmRoylance, Abrams, Berdo [21] Appl. No.. 279,083 & Kaul [30] A i fi d vi i i i :riority Data 7lll003 [57] v ABS CT t ug 6 er an S A Hall-voltage dev1ce compnsmg means for generat- 52 US. 01 310 11 310 DIG. 3, 324 45 ing a magnetic field and h fluid-Containing body in this isli 1m. 01. G2ld 702 field, which fluid contains Charged pahhcles- The [58] Field of Search 324/45; 31'0/11, DIG. 3; vice hmher comprises means for moving the body 73/614 ative to the magnetic field in a plane essentially normal to said field and means for collecting and measur- 56] References Cited ing the Hall-voltage produced in the body upon such a movement, the latter means consisting of two elec- UNITED STATES PATENTS trodes connected to spaced apart points of the fluid. 2,982,214 5/l96l Cochran 310/11 3,004,158 10/1961 Steimel 310/11 4 Claims, 2 Drawing Figures HALL-VOLTAGE DEVICE The invention relates to a Hall-voltage device comprising means for generating a magnetic field and a body in this field having means for moving electrically charged particles in a plane essentially normal to the magnetic field and means for collecting and measuring the Hall-voltage produced in the body upon such a movement.

In the conventional Hall-voltage devices of the above type the body is usually positioned in a magnetic field and comprises a pair of electrodes by means of which a current is passed through the body and a pair of electrodes at which the produced Hall-voltage can be collected.

It is an object of the invention to eliminate in a device of this type the presence of the current supply electrodes and, consequently, also that of the current supply required for feeding the Hall-voltage device, and to gain a knowledge of the properties of the particles transferring the. Hall-voltage.

In accordance with the invention, the body comprises a fluid containing charged particles and means are present to impart to the body a movement relative to the magnetic field, the means for collecting the Hallvoltage consisting of two electrodes connected to spaced apart points of the fluid.

More particularly, in accordance with the invention the body consists of a cylinder in the form of a flat, hollow box comprising a cover, a bottom and a perforated partition parallel thereto and dividing the interior of the box into two chambers, each chamber comprising a diametric channel and a peripheral channel, a fluid in each channel at least one having charged particles distributed therein (emulsion, colloid) being contained in these channels, the electrodes being mounted on the cover and on the bottom of the box, respectively, and being conductively connected to the fluid in the box.

ln a simpler embodiment the body consists of a hollow box comprising one chamber, wherein the perforated partition is not used, while for the rest the structure is identical to that of the box comprising two chambers.

The box may be of a simple structure and may consist of transparent discs of synthetic material having a thickness of some tenths of millimeters, which are superimposed in fully sealing fashion and within which the hollow space containing the fluid is formed by holes in the central disc and all electrically conductive portions of which may consist of e.g. silver paint. These discs are adapted for single use. The particles in the fluid are impelled outwardly by the centrifugal force generated by the motor. The particles are in rapid rotation and are in a high magnetic field that exerts a Hallvoltage on the particles and affects the movement caused by the centrifugal force.

Finally, in accordance with the invention the electrodes can be connected through mercury contact systems to a Hall-voltage meter.

The invention will be elucidated hereinafter with reference to the drawing, in which:

FIG. 1 shows a vertical cross-section of an embodiment of a device according to the invention;

FIG. 2 shows a view, partly in cross-section, of an embodiment of a component of a device in accordance with the invention.

As appears from FIG. 1, in the case of the embodiment in accordance with the invention shown therein the Hall-voltage device comprises a motor 1 adapted to drive a metal'shaft 2 at a high velocity of e.g. 10,000 revolutions per minute. The shaft 2 extends through a bore 3, which is provided in a magnet component 4 that magnetically cooperates with a magnet component 5 positioned below and aligned with the magnet component 4, which magnet component 5 also comprises a bore.

At the lower end of the shaft 2 there is provided a hollow box containing fluid, which is represented in the drawing by the disc 6, the'shaft 2 extending through this disc. The disc 6 is secured to the shaft'2 by means of a metal ring 7 positioned on top of the disc 6 and a pivot 8 of insulating material positioned below the disc, which pivot 8 is externally provided with an electrically conductive coating 9. This pivot fits a cone-shaped enlargement 10 of a sleeve 11 of synthetic material provided in a bore in the magnet component 5, which bore is coaxial with the bore 3 in the magnet component 4. The shaft 2 is secured to the pivot 8 by means of screw thread cut in the end of the shaft.

The disc 6 shown in FIG. 1 consists of a box as shown in FIG. 2 of the drawing.

As appears from this FIG. 2, use is made of a box composed of a cover 23, a bottom 24 and an intermediate, perforated partition 25, which components all consist of synthetic material, eg teflon.

The top of the cover 23 is provided with a circular conductive coating 26 which extends in axial and downward direction along the shaft 2. Below the cover 23 there are provided three components of synthetic material having a specific shape, which are formed and arranged such that below the cover 23 a diametric and outwardly flaring channel 27 and an annular channel 28 adjacent the periphery of the cover are formed.

The top of the partition 25 is provided with an annular conductive coating 29 which is connected to an annular conductive coating 31 by means of a conductive strip 30.

Furthermore, a second, more outwardly positioned, annular conductive coating 32 is provided on the same side of the partition 25 concentrically with the coating 31.

At this place the partition 25 is provided with perforations 33 filled with an electrically conductive compound, which perforations 33 terminate in an annular conductive coating 34 on the underside of the partition 25, a second annular conductive coating 35 being provided coaxially within this annular coating 34. The annular conductive coating 35 is connected to an annular conductive coating 37 by means of a conductive strip 36.

It is observed thatthe bore in the partition 25 has a diameter that is larger than that of the shaft 2, so that the partition 25 is not in contact with this shaft. The same applies to the bottom 24 of the box, which will be described hereinafter. This bottom is arranged in a similar manner as the cover 23 of the box, that means that also here a diametric 38 and an annular channel 39 are present. The top of the bottom is provided with an annular conductive coating 40 which extends along the inside of the bore in the bottom 24 to an annular conductive coating 41 provided on the underside of the bottom 24, which coating 41, just as in the embodiment shown in F IG. 1, is connected to the conductive coating 9 on the pivot 8. It is once more observed that the bore in the bottom has a diameter larger than that of the shaft 2, so that the bottom is not in contact with this shaft.

The fluids the properties of which are to be determined or compared are inserted into the metallically interconnected hollow spaces of the box structure adapted for receiving these fluids by means of, for example, an injection needle which is inserted from the outside through the diametric channels 27 and 38 into the annular channels 28 and 39, respectively.

When during operation of the device the disc 6, which represents the box comprising the fluid containing the electrically charged particles, is rotated by the motor 1 in the magnetic field generated by the magnet components 4 and 5, which magnetic field is essentially normal to the disc 6, a Hall-voltage is produced between the coatings 26 and 41 of the disc 6, which voltage affects the charged particles in the fluid.

In order to be able to measure the influence of the Hall-voltage, the presence of which appears from the deposition of the charged particles on the electrodes, the top end of the shaft 2 is provided with a mercury contact system. This system comprises a container 18 mounted on the shaft 2, which container is open at its top and is partially filled with mercury that is in conductive contact with the shaft 2. Upon rotation of the shaft 2 this mercury is urged upwardly along the walls of the container, thereby making contact with a probe 19 connected to an output terminal 20.

In order to make a connection between the coating 17 and the outside, an amount of mercury is contained in the sleeve 11 in the bore of the magnet component 5. The height of the amount of mercury within the sleeve 11 can be adjusted by means of a siphon device 21 in such a manner that the mercury is in conductive contact with the metal coating 9 of the pivot 8. The mercury in the member 21 is connected to the other output terminal 22 of the device in an appropriate manner.

It is preferable to provide the shaft 2 with a rubber coupling so as to ensure decoupling relative to the rest of the device in case the rotatable shaft would get jammed, thereby protecting the device against damages.

lt will be clear that in the above manner a Hallvoltage can be generated by means of the device in accordance with the invention without using a current supply and associated current supply electrodes, which Hall-voltage can provide a better insight in the properties of the different particles in the fluid, which are successively separated at the electrodes as a result of the influence of the centrifugal force, which may be supported or fully inhibited by the effect of the magnetic field.

I claim: 1. A Hall voltage device comprising means for generating a magnetic field; a body mounted for movement in said field, said body having an interior cavity; a fluid containing electrically charged particles disposed in said cavity; means for imparting to said body movement in a plane essentially normal to said field to produce migration of the particles in said fluid as a result of the interaction of said field and said movement; and electrode means disposed in said cavity for conductively contacting said fluid and collecting the Hall-voltage produced in said body as a result of said migration. 2. A device according to claim 1 wherein said means for generating a magnetic field includes a magnetic circuit having a gap therein defined by spaced planar boundaries; said body comprises a cylinder, and said device further includes shaft means for supporting said body for rotary movement about an axis essentially coincident with the centerline of said gap. 3. A device according to claim 1 wherein said body comprises a hollow cylindrical box having a cover, a bottom and a perforated partition parallel to and between said cover and said bottom and dividing the cavity into two chambers, each said chamber having means defining a diametric channel and a peripheral channel for containing said fluid, said electrode means being mounted in said cover and said bottom of said box. 4. A device according to claim 1 and further comprising a meter, and mercury contact means for electrically connecting said electrode means to said meter. 

1. A Hall voltage device comprising means for generating a magnetic field; a body mounted for movement in said field, said body having an interior cavity; a fluid containing electrically charged particles disposed in said cavity; means for imparting to said body movement in a plane essentially normal to said field to produce migration of the particles in said fluid as a result of the interaction of said field and said movement; and electrode means disposed in said cavity for conductively contacting said fluid and collecting the Hallvoltage produced in said body as a result of said migration.
 2. A device according to claim 1 wherein said means for generating a magnetic field includes a magnetic circuit having a gap therein defined by spaced planar boundaries; said body comprises a cylinder, and said device further includes shaft means for supporting said body for rotary movement about an axis essentially coincident with the centerline of said gap.
 3. A device according to claim 1 wherein said body comprises a hollow cylindrical box having a cover, a bottom and a perforated partition parallel to and between said cover and said bottom and dividing the cavity into two chambers, each said chamber having means defining a diametric channel and a peripheral channel for containing said fluid, said electrode means being mounted in said cover and said bottom of said box.
 4. A device according to claim 1 and further comprising a meter, and mercury contact means for electrically connecting said electrode means to said meter. 